B12 IS in mushrooms afterall.
Am I the last vegan on the planet to hear about this? It seems that earlier this year, researchers at the University of Western Sydney finally proved that B12 is bio-available in mushrooms, "in exactly the same form as in beef liver and fish".
Vitamin B12
There has long been speculation about whether or not mushrooms provide vitamin B12, a vitamin normally associated with animal foods. In 1987, the Australian Government Analytical Laboratories found appreciable amounts of B12 in mushrooms.
Based on this analysis, the mushroom industry then included B12 as a nutrient in their promotional material and advertising. The B12 level was disputed by some nutrition professionals who believed that only animal sources can provide B12, while others wanted to know whether the B12 claimed to be found was bio-available.
In early 2009, researchers at the University of Western Sydney completed ground-breaking research on the B12 content of button mushrooms. Their detailed experiments on mushrooms of all sizes and stages of growth from around Australia conclusively proved that:
A. Mushrooms do have B12 present. It is on both the surface of the mushroom and in the flesh of the mushroom. The majority of B12 is in the surface of the cup of the mushroom.
B. The B12 present is bio-available, in exactly the same form as B12 in beef liver and fish.
C. The average amount of B12 in mushrooms is still to be calculated, but is not likely to be more than 5% of the RDI. However, that level may be an important amount for a vegan over a lifetime.
The results of the vitamin B12 study will be published in a peer reviewed scientific journal. We shall give you the full details when this occurs.
From http://www.mushroomsforlife.net/scientific_facts.html Then I found this abstract in the Journal of Agricultural and Food Chemistry that confirms it: http://pubs.acs.org/doi/abs/10.1021/jf9010966 (if anyone wants the full pdf article just message me with your email address and I will forward it).